Norfloxacin interaction with antacids and minerals

Br J Clin Pharmacol. 1992 Jan;33(1):115-6. doi: 10.1111/j.1365-2125.1992.tb04010.x.


The urinary excretion of norfloxacin was measured in eight healthy volunteers after its co-administration with a variety of over-the-counter preparations, each containing a different metal ion. Commonly used doses of ferrous sulphate, zinc sulphate, aluminium hydroxide and magnesium hydroxide reduced the 24 h urinary excretion of norfloxacin by 50 to 90%. Bismuth subsalicylate had no significant effect. In vitro experiments demonstrated the formation of complexes between norfloxacin and iron, zinc, aluminium, and magnesium ions, respectively. Many pharmaceuticals contain the same metal ions that caused significant interactions with norfloxacin. The efficacy of norfloxacin treatment may be compromised when it is taken concurrently with preparations containing these metal ions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antacids / pharmacology*
  • Biological Availability
  • Drug Interactions
  • Female
  • Humans
  • Iron / pharmacology
  • Male
  • Minerals / pharmacology*
  • Norfloxacin / urine*
  • Zinc / pharmacology


  • Antacids
  • Minerals
  • Iron
  • Zinc
  • Norfloxacin